The kidnappers of the mother-in-law of Bernie Ecclestone threatened to send back her severed head in a shopping bag, the Formula One billionaire has revealed.
Speaking after Aparecida Schunk, the 67-year-old mother of his wife Fabiana Flosi had been freed, Mr Ecclestone recalled the full horror of the nine days she was missing after being snatched from her home in San Paulo, Brazil.
The threat came in an email sent by the kidnappers a week after they had taken Ms Schunk and demanded a ransom of £28 million.
Mr Ecclestone also joked that he never intended to pay a ransom for the release.
The 85-year-old spoke proudly of the involvement of his wife in the police operation in an interview with Tom Bower of the Sunday Times.
Ms Schunk was released unharmed last week, with no ransom paid.
Ecclestone said: "I'm so proud of Fabiana. She worked with the police until 4am every night. She was terrific."
Asked about the ransom demand by the gang, he said in the interview: "I never intended to pay them," and added joking: "All my friends know that I wouldn't pay a penny for a mother-in-law."
One of Mr Ecclestone's pilots, Mr Silva Faria, has been arrested by police on suspicion of his involvement with the kidnap.
Ms Flosi said of the pilot: "I just can't understand it. He was always so polite and kind."
Shortly after Ms Schunck was reunited with her relatives Mr Ecclestone said he was "very happy" with the police operation that he described as "unbelievable".
"The last few days haven't been very good. This isn't a good thing to happen to you and your family," he told MailOnline at the time.
"The police officers we dealt with were fantastic, they did an unbelievable job, it was absolutely first class. We are very, very, very happy with them."
It is believed investigators monitored phone calls between the family of Ms Schunck and the captors, tracing them to the location where she was being held.
She was not harmed in the operation conducted by Sao Paulo's anti-kidnapping division. Speaking after she was freed Ms Schunk said: "I just ask that the crooks do not kidnap anyone else in Sao Paulo because they will be arrested."
According to reports her abductors had demanded £28 million for her release, later increasing it to £40 million.
Brazilian magazine Veja had reported that the ransom for Ms Flosi's mother had been demanded in pounds sterling and divided into four bags of cash.
Elisabete Sato of Sao Paulo police told the BBC that the ransom, thought to have been the largest in Brazilian history, had not been paid.
Mr Ecclestone married Ms Flosi, 38, in 2012, three years after meeting her at the Brazilian Grand Prix.
Security has emerged as the top concern at the Olympics in Brazil amid fears of violence possibly spilling over from Rio's hundreds of slums.
Authorities have said they will be prepared and that 85,000 police and soldiers will be patrolling during competition.